Problem with charging Panasonic lcr6v12p1 battery

[izua]

I've got a Panasonic lcr6v12p1 battery. specs on it say 6V 12AH/20HR.
It's a lead-acid "sealed" type. It was dead when i got it (like really dead, output was under 0.7V).

it also says constant voltage charge : 7.3-7.5 (initial currenty less than 4.8), standby use: 6.8 - 6.9.

I have a car battery charger that can charge both 6 and 12v batteries, so I used that.
I've checked the output of the charger, and of course, + on it was -. So that thing expected me to connect + to the battery + pole, and - to the battery -. Which I did.

Now, this charger thing is a pretty simple thing: a transformer with two taps (6/12), a rectifier, a switch and an ammeter (i think that's what it is). One of the wires going to the charger terminals is wrapped around (physically, not even connected) to the ammeter. It also has a "Wrong polarity" light, but this doesn't seem to work on the 6V battery (works on car batteries).

I've put my battery on charge, and the ammeter thing showed 0. If i short the poles, it goes to 100%, of course.. In a few minutes, it risen to about 25%, and it slowly declined to 10-15% in about 2 hrs, when the battery was getting pretty hot, so i removed it. what intrigues me: why did the current through the battery had to rise, before dropping? on car batteries it's always dropping, it's not rising first..

the battery showed 5.5 volts after charging. in 2 hours, it lost half of the charge. after twelve hours, it only has 0.77. It hasn't been connected to any load after charging, nor when doing the measurments.

Is it something wrong, does it need to be formatted like the nichel-types?
or isn't it good at all?

 

[mvs sarma]

lcr6v12p1 battery

The year of manufacture of the battery is not indicated. How long the battery was in service.

As the SLA battery ages, the acidic gel material dries off . there will be raise of internal resistance. With modern DMMs the open circuit potential will show high but as such the battery can't deliver load current.
as regards heating up, perhaps is it due to partial wetness in the cell reacting to the charging current. In fact it is difficult to drive in current.

Sarma

 

[izua]

battery panasonic lcr6v12p1

It hasn't been used at all, just that it hasn't been charged for over a year.

 

[mvs sarma]

dead car battery charge retention

Oh! Obviously , perhaps, you may have to forget about it and any more effort will be a waste. Go for a fresh one and deep discharge, overcharge and no discharge for prolged periods are all detrimental to these Batteries.


Sarma

 

[laktronics]

panasonic lcr6v12p1

Hi,
It is true that your battery might have gone due to deep discharge and may never recover again.
But,

I've checked the output of the charger, and of course, + on it was -. So that thing expected me to connect + to the battery + pole, and - to the battery -. Which I did.

What do you mean by + on it was - ? with respect to which point?
Again

It also has a "Wrong polarity" light.I've put my battery on charge, and the ammeter thing showed 0. If i short the poles, it goes to 100%, of course..

Why wrong polarity light? Why ammeter should show zero when charging? You are not expected to short the poles when battery is connected.
I feel you have connected the charger in reverse direction, but then I can not say why at all the battery got charged.
You have to always connect the +ve terminal (Terminal which is voltage wise +ve) to +ve of the battery and -ve of the charger to -ve of the battery for charging. If the charging current flows in the correct direction, the meter should show the current.
Please recheck your connections again and see if the battery recovers.
Regards,
Laktronics

 

[izua]

Re: charging a lcr6v12p1

I checked it with my multimeter, knowning what probe connects to ground, and what to v+, i connected the probes to the respective campls on the charger (+ to + and - to -). The voltage showed up as -7.04. So that's basically ground, IMO

The battery still acts weird. I charged it again today for a few hours, and it was able to power a tape-recorder motor for about 30 minutes, before it reached ~3 volts. it also loses charge very quick. heh, guess it's good no more..

what are the chances of making it explode if i leave it for a 12 hr charge? or a double voltage charge?

edit: shorting the charge poles, of course, not the battery poles
i checked out the wrong polarity light (if you put your battery in reverse). it's basically a bimetal that heats up and disconnects the whole thing (explains why it only works after a few seconds).

 

[laktronics]

Re: charging a lcr6v12p1

Hi,
If you have connected +ve(normally Red terminal) of the multimeter to +ve of the charger and -ve(normally black terminal) of the multimeter to -ve of the charger, it should show only +ve voltage and not negative voltage even if the charger +ve terminal is internally connected to earth, since the multimeter terminals are of floating type. If it shows -ve, then the so called +ve terminal of the charger is not +ve, it is negative and it should go to the -ve of the battery. You can check the correctness of your multimeter leads using a simple dry cell with known polarity.
Are you getting the current indication in the Ammeter now, when battery is charged?
May be you can try a few more cycles of charge /discharge to see if the battery charge retention improves for subsequent cycles. I do not see much problem for longer duration charging at rated voltage, but at double voltage it is a BIG NO.
Even under normal voltage, if the battery gets hot, better to stop torturing it further.
Regards,
Laktronics